Some 150-200 l of dialysis liquid are usually required to carry out a typical dialysis treatment. The dialysis liquid is generally produced in the dialysis apparatus using two dialysis concentrate liquids and water which are, for example, mixed in a ratio of 1/35. For the production of the dialysis liquid, an alkaline dialysis concentrate liquid, which typically is a sodium hydrogen carbonate solution of a defined concentration, and an acidic dialysis concentrate liquid, in which all other ingredients necessary for the dialysis liquid are contained in the required concentration, are homogeneously mixed with water.
Up to 51 of acidic dialysis concentrate solution is required to carry out a typical dialysis treatment, with 90% thereof being water. A dialysis concentrate production system has previously been described in DE 103 13 965 B3 where a dry concentrate is homogeneously mixed with water to obtain the dialysis concentrate liquid. The dry concentrate is supplied in a mobile and reusable interchangeable container having two ports for introducing and discharging liquid, respectively. Both ports are connected in situ to a stationary production system which, among others, comprises a so-called storage container, a delivery pump downstream of an outlet of the storage container, two water jet pumps, and a plurality of valves.
The process of producing the dialysis concentrate liquid starts by introducing a precisely measured volume of water into the storage container. By switching shut-off valves in an adequate manner, the water is then pumped from the storage container into the interchangeable container, whereby the dry concentrate is dissolved in the water. As soon as the closed interchangeable container is completely filled with liquid, the liquid flows through a drain at the upper end of the interchangeable container back to the storage container. The liquid is pumped to circulate between the storage container and the interchangeable container and back until the dry concentrate is dissolved completely and homogeneously in the entire liquid volume.
The liquid is pumped under pressure into the interchangeable container and flows under pressure from the outlet to the storage container. The interchangeable container is thus continuously exposed to overpressure and must not leak since significant amounts of liquid may otherwise be lost without being readily noticed. This may also lead to an undesirable change in the concentration of the chemical ingredients of the dry concentrate in the total liquid.